The invasive Asian carps seem to have bypassed the electric barrier built to protect the North American Great Lakes from potential ecological disaster.

Bighead carp Asian carps might have jumped the last line of defense for the Great Lakes

Bighead and Silver carp DNA has been found in the Calumet River, Des Plaines River and at the confluence of the Calumet Sag Channel and the Chicago Sanitary and Ship Canal, federal and state officials announced Friday.

U.S. authorities regularly test for Asian carp DNA in suspended particles floating in river currents in this region, and positive test results have now appeared less than seven miles from Lake Michigan.

The carps are believed to have jumped over the electrical barrier commonly referred to as the “last line of defense” for the Great Lakes.

Authorities are now trying to locate the carps and catch them.

Why are the Asian carps such unwelcomed visitors?

The Asian carps wreck havoc with the native ecosystem by outcompeting local species for food.

They were deliberately brought to North America by catfish farmers to keep farm ponds clean, but managed to escape into the wild during a series of powerful flooding incidents in the 1990s. Since then, they have gradually expanded their range up the Mississippi and Illinois rivers.